Make http paths configurable

[colmsnowplow]

Currently the http sink will generate a vendor/version format path consistent with one of:

• the old .png endpoint
• the i endpoint
• tp1
• tp2
• a randomly generated custom path

However, depending on what we're testing, random distributions of these are problematic - for example we may want to load test the collector using mostly the tp2 and i endpoints, since those are most commonly used.

Suggest implementing a configuration similar to the eventFrequencies or methodFrequencies configs - whereby we can weight the distribution or simply turn some of them off.

A stretch goal/bonus would be to add an additional option, to provide a path via the config, and give that a weight also. This might be tricky to implement but would allow us to test custom paths.